Revision of standard molar enthalpies of formation of glycine and l-alanine in the gaseous phase on the basis of theoretical calculations

Assessment of Gaussian-4 theory for the computation of enthalpies of formation of large organic molecules

“…The similar picture is observed for methionine (108): the difference between experiment and theory is reduced from 16 kJ/mol to 7 kJ/mol or -4 kJ/mol if the available experimental data on D sub H T [82,83] are adjusted to D sub H 298 by the same way as for 109. Particular attention in Table 5 [84,85]. As is seen from Table 5, the values of D f H 298 obtained by isodesmic reaction method are very close to those calculated from atomization energies.…”

Enthalpies of formation of β-alanine, sarcosine, and 4-aminobutanoic acid from quantum chemical calculations

“…The values of enthalpy of formation of reference compounds used in isodesmic reactions were taken from [21] except for the amino acids. The D f H m ðg;298:15 KÞ values for glycine (H 2 N-CH 2 -COOH) and alanine (H 2 N-CH(CH 3 )-COOH) are those recommended in our previous study {(À393.7 ± 1.5) and (À424.8 ± 2.0)} kJ Á mol À1 , respectively [2], while the values recommended in table 6 were used for b-alanine and sarcosine.…”

“…Earlier the GAVs for amino acids were obtained by Domalski and Hearing [6] using available experimental data. However, as is seen from our previous work [2] and this work, some of these experimental data have large inaccuracies and therefore the GAVs for amino acids should be revised.…”

“…In previous works, the D f H m ðg; 298:15 KÞ values were calculated for DNA and RNA nucleobases [1] and two amino acids [2] by Gaussian-3X (G3X) method. It has been shown that theoretical calculations could be used to test the accuracy of experimental values and recommend more reliable enthalpies of formation for compounds in the solid phase and enthalpies of sublimation.…”

Studies on crystals of d-, l-, and dl-alaninato nickel(II) complexes

“…The synthesis, spectrochemical properties, structure, stability, thermochemical study, and characterization of complexes of copper(II), nickel(II), cobalt(II), and zinc(II) with histidine, glycine, alanine, and other amino acids have previously been reported [8][9][10][11][12][13][14]. Standard molar enthalpies of formation of glycine and alanine in the gaseous phase on the basis of theoretical calculations have recently been studied [15]. In thermodynamics and physical chemistry, thermochemistry is the study of the energy evolved or absorbed in chemical reactions and any physical transformations, such as melting and boiling.…”